CN112400116A

CN112400116A - Magnetic impedance sensor and method for manufacturing magnetic impedance sensor

Info

Publication number: CN112400116A
Application number: CN201980043095.6A
Authority: CN
Inventors: 楠田达文
Original assignee: Nidec Read Corp
Current assignee: Nidec Advance Technology Corp
Priority date: 2018-06-27
Filing date: 2019-05-21
Publication date: 2021-02-23
Also published as: US11953562B2; US20210109169A1; JP7468344B2; WO2020003815A1; KR20210023873A; JPWO2020003815A1

Abstract

The magnetic impedance sensor 1A includes: an amorphous wire 2; an insulator layer 3 formed on the outer peripheral surface of the amorphous wire 2; and an X-axis coil 6X, Y axial coil 6Y and a Z-axis coil 6Z formed spirally on the outer peripheral surface of the insulator layer 3, the X-axis coil 6X, Y axial coil 6Y and the Z-axis coil 6Z are formed of conductive layers, and the X-axis coil 6X, Y axial coil 6Y and the Z-axis coil 6Z are arranged in directions orthogonal to each other.

Description

Magnetic impedance sensor and method for manufacturing magnetic impedance sensor

Technical Field

The present invention relates to a magnetic impedance sensor and a method of manufacturing the magnetic impedance sensor, and more particularly, to a technique of manufacturing a magnetic impedance sensor with a simple structure.

Background

Conventionally, there is known a Magneto-Impedance (MI) sensor including: a magnetic conductor comprising an Amorphous wire (Amorphous wire); and an electromagnetic coil wound around the magnetic conductor via an insulator (see, for example, patent document 1). The patent literature describes the following MI sensors: a metal film is formed by vacuum evaporation of a metal material containing copper on the outer periphery of an insulator, and then an electromagnetic coil is formed by selective etching.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3781056

Disclosure of Invention

In general, an MI sensor is configured by arranging three (or two) MI elements orthogonal to each other in the X, Y, Z direction as in the above-described conventional technique in order to sense static characteristics or dynamic characteristics of an object in three dimensions (or two dimensions). The central axis of each MI element is formed by winding a coil (pickup coil) around an amorphous magnetic conductor. Then, a pulse current flows through the magnetic conductor, and the reaction is detected by the coil.

In this configuration, since the MI element itself is small, the work of mounting the MI elements on the substrate by combining them becomes complicated. In order to flow a pulse current to both ends of the magnetic conductor included in the center, it is necessary to take out the wires connected to both ends to the outside. That is, for example, in a three-dimensional MI sensor, a total of six wires need to be taken out from each magnetic conductor in three MI elements.

In addition, in the case of an MI element using a semiconductor process, since an upper portion and a lower portion of a coil need to be formed separately, the number of turns cannot be freely increased. Further, the coil cannot be made circular in cross section, and the distance between the magnetic conductor and the coil is not constant, resulting in an electric loss.

Further, in the case of an MI element in which a coil is formed by winding a wire material such as an enamel wire around a hollow cylindrical material, the number of turns of the coil can be set relatively freely. However, the magnetic conductor must be inserted as a core wire after the coil is formed, with the result that a space between the core wire and the coil is generated, and therefore, an electrical loss is generated. Such electric loss becomes a factor of variation in detection accuracy in the MI element, and becomes a cause of individual difference of the MI element.

Further, it is necessary to apply high-frequency pulses to the magnetic conductors X, Y, Z in the respective directions from different circuits, or to externally connect the magnetic conductors to each other to apply pulses. However, in the former, it is difficult to make the high-frequency pulses in each direction strictly the same, and in the latter, the output is likely to vary due to the resistance of the connection portion, which causes an individual difference in the direction of X, Y, Z in the MI sensor.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an MI sensor and a method of manufacturing the MI sensor, which can simplify the mounting work, reduce the electric loss by making the distance constant without leaving a space between the magnetic conductor and the coil, and suppress the occurrence of individual differences between the MI sensors and the individual differences between the MI sensors in the direction X, Y, Z.

In order to solve the above problems, the present invention provides an MI sensor having the following configuration and a method of manufacturing the MI sensor.

An MI sensor according to an example of the present invention includes: a linear magnetic conductor; an insulator layer formed on an outer peripheral surface of the magnetic conductor; and a first coil, a second coil, and a third coil that are formed in a spiral shape on an outer peripheral surface of the insulator layer, wherein the first coil, the second coil, and the third coil are formed of a conductive layer, and the first coil, the second coil, and the third coil are arranged in mutually orthogonal directions.

A method for manufacturing an MI sensor according to an example of the present invention includes: an insulating step of forming an insulator layer on an outer peripheral surface of the linear magnetic conductor; a conductive layer forming step of forming a conductive layer on an outer peripheral surface of the insulator layer; a resist step of forming a resist layer on an outer peripheral surface of the conductive layer; an exposure step of forming a first channel portion, a second channel portion, and a third channel portion in a spiral shape on an outer peripheral surface of the resist layer by exposing the resist layer with laser light, respectively, forming a first gap around the resist layer between the first channel portion and the second channel portion on the outer peripheral surface of the resist layer, and forming a second gap around the resist layer between the second channel portion and the third channel portion on the outer peripheral surface of the resist layer; an etching step of etching the resist layer as a cover material to remove the conductive layer in the first channel portion, the second channel portion, the third channel portion, the first gap, and the second gap, thereby forming a first coil from the conductive layer remaining around the first channel portion, a second coil from the conductive layer remaining around the second channel portion, and a third coil from the conductive layer remaining around the third channel portion; and a bending step of bending the magnetic conductor and the insulator layer between the first coil and the second coil and between the second coil and the third coil, thereby arranging the first coil, the second coil, and the third coil in directions orthogonal to each other.

Drawings

Fig. 1 is a perspective view showing an MI sensor according to a first embodiment.

Fig. 2 is a front view showing an MI sensor in the middle of manufacturing.

Fig. 3 is a partial sectional view taken along line III-III of fig. 2.

Fig. 4 is a diagram showing the respective manufacturing steps of the MI sensor of the first embodiment.

Fig. 5 is a perspective view showing an MI sensor of a second embodiment.

Detailed Description

< MI sensor 1A (first embodiment) >

First, the configuration of a magneto-impedance sensor (hereinafter, simply referred to as an "MI sensor") 1A according to a first embodiment of the present invention will be described with reference to fig. 1 to 3. The MI sensor 1A performs magnetic sensing by utilizing a so-called MI phenomenon in which an induced voltage is generated in the coil 6 (the X-axis coil 6X, Y axis coil 6Y and the Z-axis coil 6Z) according to a change in current flowing through a linear magnetic conductor (the amorphous wire 2 in the present embodiment).

The MI phenomenon occurs with respect to a magnetic conductor including a magnetic material having an electron spin arrangement in a peripheral direction with respect to a direction of a supplied current. When the current flowing through the magnetic conductor is changed rapidly, the magnetic field in the peripheral direction is changed rapidly, and the spin direction of the electrons is changed by the action of the change in the magnetic field. The MI phenomenon is a phenomenon that occurs due to changes in internal magnetization, impedance, and the like of the magnetic conductor at this time.

As shown in fig. 1 and 3, in the MI sensor 1A of the present embodiment, an amorphous wire 2, which is a linear body having a circular outer peripheral shape such as CoFeSiB having a diameter of several tens μm or less, is used as a linear magnetic conductor. In the present embodiment, by using the amorphous wire 2 excellent in the magnetic induction performance as the magnetic conductor, the output voltage per one turn of the coil 6 is increased to reduce the number of windings, and the length in the axial direction of the MI sensor 1A is formed short. An insulator layer 3, which is an acrylic resin, is formed on the outer periphery of the amorphous wire 2 so that the outer peripheral shape of the cross section becomes a circular shape. As the magnetic conductor applied to the MI sensor 1A, a magnetic conductor in which a linear body is covered with a magnetic anisotropic thin film, Permalloy (Permalloy) which is a Ni — Fe alloy, or the like may be used instead of the amorphous wire 2 used in the present embodiment.

Specifically, the outer peripheral shape of the insulator layer 3 is formed in a circular shape concentric with the outer peripheral shape of the amorphous wire 2, that is, the thickness of the insulator layer 3 is uniform in the circumferential direction. More specifically, the amorphous wire 2 is immersed in an electrodeposition paint in which an acrylic resin material is dispersed in a solution in an ionic state, and a voltage is applied between the amorphous wire 2 and the electrodeposition paint in the tank, whereby the acrylic resin in an ionic state is electrodeposited on the amorphous wire. According to the method, the thickness of the insulating layer can be controlled by the applied voltage. The electrodeposition coating material formed on the surface of the amorphous wire 2 in the above manner is sintered at a high temperature of, for example, 100 degrees or higher, thereby forming the insulator layer 3. In the present embodiment, the core wire S is composed of the amorphous wire 2 and the insulator layer 3.

An X-axis coil 6X as a first coil, a Y-axis coil 6Y as a second coil, and a Z-axis coil 6Z as a third coil are spirally formed on the outer peripheral surface of the insulator layer 3. As shown in fig. 1, each of the coils 6X to 6Z is formed of a conductive layer. Specifically, the conductive layers of the coils 6X to 6Z are formed of two layers, i.e., the electroless-plated layer 4 and the electrolytic-plated layer 5 formed on the outer peripheral surface of the electroless-plated layer 4 (see fig. 3). The configuration of the conductive layer of the coils 6X to 6Z in the present embodiment is an example, and the conductive layer may have another configuration. For example, the conductive layers of the coils 6X to 6Z may be formed by sputtering or the like.

As shown in fig. 1, the X-axis coil 6X, Y, the axis coil 6Y, and the Z-axis coil 6Z are arranged with the core wires S bent between the X-axis coil 6X and the Y-axis coil 6Y, and between the Y-axis coil 6Y and the Z-axis coil 6Z, respectively, so as to be axially centered in the X-axis direction, the Y-axis direction, and the Z-axis direction. That is, the X-axis coil 6X, Y, the axis coil 6Y, and the Z-axis coil 6Z are arranged in directions orthogonal to each other. That is, the X-axis coil 6X, Y, the axis coil 6Y, and the Z-axis coil 6Z are arranged in directions orthogonal to each other. Further, the X-axis coil 6X, Y, the axial coil 6Y, and the Z-axis coil 6Z may be arranged in directions orthogonal to each other in a state where the core wires S are partially cut off between the X-axis coil 6X and the Y-axis coil 6Y and between the Y-axis coil 6Y and the Z-axis coil 6Z and connected again.

As shown in fig. 1, both end portions of the X-axis coil 6X, Y and the Z-axis coil 6Z are formed as ring-shaped coil electrodes 6T that are wound around the insulator layer 3. To each coil electrode 6T, wires 7X to 7Z for measuring induced voltages generated in the coils 6X to 6Z are connected.

Fig. 2 is a front view of the MI sensor (hereinafter, referred to as a "linear sensor") 1 before the core wire S is bent. In the linear sensor 1, a first coil 6A, a second coil 6B, and a third coil 6C are formed. A first groove GP1 is formed in the first coil 6A in a spiral shape, a second groove GP2 is formed in the second coil 6B, and a third groove GP3 is formed in the third coil 6C.

A first gap GQ1 of only the core wire S is formed between the first coil 6A and the second coil 6B, and a second gap GQ2 of only the core wire S is formed between the second coil 6B and the third coil 6C. Further, a first terminal GT1 of only the core wire S is formed on the outer end side of the first coil 6A, and a second terminal GT2 of only the core wire S is formed on the outer end side of the third coil 6C. In the linear sensor 1 configured as described above, the core wire S is orthogonally bent at the first gap portion GQ1 and the second gap portion GQ 2. Thus, the MI sensor 1A in which the first coil 6A, the second coil 6B, and the third coil 6C are orthogonal to each other as the X-axis coil 6X, Y, the axis coil 6Y, and the Z-axis coil 6Z, respectively, is configured.

Next, a method for manufacturing the MI sensor 1A (a step before manufacturing the linear sensor 1) will be described with reference to fig. 4. In fig. 4, (a) shows the amorphous wire 2 before the insulating step, (b) shows the state after the insulating step, (c) shows the state after the electroless plating step, (d) shows the state after the electrolytic plating step, (e) shows the state after the resist step, (f) shows the state after the exposure step, (g) shows the state after the etching step, and (h) shows the state after the resist removing step. Since the linear sensor 1 repeats the same structure in the longitudinal direction, only one end portion (the periphery of the first coil 6A) side is illustrated in fig. 4, and illustration of the other end portion side is omitted.

In manufacturing the MI sensor 1 of the present embodiment, as shown in fig. 4 (a), an amorphous wire 2, which is a linear body having a circular outer peripheral shape, is prepared. Then, as shown in fig. 4 (b), an insulator is applied to the outer periphery of the amorphous wire 2 to form an insulator layer 3 (insulating step). At this time, as shown in fig. 3, the outer peripheral shape of the insulator layer 3 in the cross section is formed in a circular shape concentric with the outer peripheral shape of the amorphous wire 2, that is, the thickness of the insulator layer 3 is uniform in the circumferential direction.

Next, a conductive layer composed of the electroless-plated layer 4 and the electrolytic-plated layer 5 is formed on the outer peripheral surface of the insulator layer 3 (conductive layer forming step). Specifically, as shown in fig. 4 (c), electroless Cu plating is performed to form an electroless plated layer 4 on the outer peripheral surface of the insulator layer 3 (electroless plating step). In this step, electroless Au plating may be used. Then, as shown in fig. 4 (d), an electrolytic plating layer 5 is formed on the outer peripheral surface of the electroless plating layer 4 by performing electrolytic Cu plating (electrolytic plating step). In this step, electrolytic Au plating may be used. As described above, in the present embodiment, the metal film is formed on the insulator layer 3 by electroless plating and electrolytic plating.

Next, the amorphous wire 2 having the electrolytic plating layer 5 formed thereon is immersed in a photoresist bath containing a photoresist solution, and then pulled up at a predetermined speed (for example, a speed of 1 mm/sec), thereby forming a resist layer R on the outer peripheral surface of the electrolytic plating layer 5 as shown in fig. 4 (e) (resist step).

Next, as shown in fig. 4 (f), the resist layer R is exposed to a laser beam, and the laser-exposed portion is dissolved in a developer, thereby forming a spiral first channel portion GA1 and a spiral second channel portion GA2 (and a third channel portion GA3 (not shown)) on the outer peripheral surface of the resist layer R. Further, a first gap GB1 is formed around the resist layer R between the first channel portion GA1 and the second channel portion GA2 on the outer peripheral surface of the resist layer R (and a second gap GB2, not shown, is formed around the resist layer R between the second channel portion GA2 and the third channel portion GA 3). Further, a first end GC1 (and a second end GC2 (not shown) that surrounds the resist layer R around the outer end side of the third trench portion GA3) is formed on the outer peripheral surface of the resist layer R around the resist layer R on the outer end side of the first trench portion GA 1. Thereby, the electrolytic plating layer 5 of the first channel portion GA1, the second channel portion GA2, the third channel portion GA3, the first gap GB1, the second gap GB2, the first end portion GC1, and the second end portion GC2 is exposed (exposure step).

The exposure with the laser light in the exposure step is performed by rotating the amorphous wire 2 on which the resist layer R is formed with the central axis thereof as an axis and displacing the amorphous wire in the axial direction. In this embodiment mode, a positive type photoresist is used in which various grooves (a first channel portion GA1, a second channel portion GA2, a third channel portion GA3, a first gap GB1, a second gap GB2, a first end portion GC1, and a second end portion GC2) are formed in the resist layer R by dissolving a laser-exposed portion in a developer. In this step, a negative photoresist in which a portion not exposed to laser light is dissolved in a developer to form various grooves in a resist layer may be used.

In the present embodiment, as shown in fig. 4 (f), the first end portion GC1, the first channel portion GA1, the first gap GB1, and the second channel portion GA2 are formed to be spaced apart from each other. Similarly, the second channel portion GA2, the second gap GB2, the third channel portion GA3, and the second end portion GC2 are formed to be spaced apart from each other.

Next, the amorphous wire 2 having the resist layer R formed with the various grooves is immersed in an acidic electrolytic polishing solution and subjected to electrolytic polishing, thereby performing etching using the resist layer remaining on the outer periphery of the electrolytic plating layer 5 as a mask material. Thereby, as shown in fig. 4 (g), the electroless plated layer 4 and the electrolytic plated layer 5 in the portions where the various grooves are formed in the resist layer R are removed (etching step).

As shown in fig. 4 (g), the spiral first groove GP1 is formed in the electroless-plated layer 4 and the electrolytic-plated layer 5 at the portion where the first channel GA1 is formed. Similarly, a spiral second groove GP2 is formed in the portion where the second channel portion GA2 is formed, and a spiral third groove GP3 is formed in the portion where the third channel portion GA3 is formed. That is, in this step, the first coil 6A is formed of the electroless-plated layer 4 and the electrolytic-plated layer 5 remaining around the first channel portion GA 1. Similarly, the second coil 6B and the third coil 6C are formed by the electroless-plated layer 4 and the electrolytic-plated layer 5 remaining around the second channel portion GA2 and the third channel portion GA 3.

In addition, a first gap GQ1 and a second gap GQ2 are formed in a portion where the first gap GB1 and the second gap GB2 are formed. In addition, a first terminal GT1 and a second terminal GT2 are formed at portions where the first end GC1 and the second end GC2 are formed.

In the present embodiment, as described above, the first channel portion GA1 is formed to be spaced apart from the first end portion GC1 and the first gap GB 1. In this way, in the etching step, the electroless-plated layer 4 and the electrolytic-plated layer 5 remaining at both end portions of the first coil 6A are formed into the annular coil electrode 6T that surrounds the insulator layer 3 once. Similarly, the second channel portion GA2 is formed to be spaced apart from the first gap GB1 and the second gap GB2, whereby the coil electrodes 6T are formed at both ends of the second coil 6B. Similarly, the third channel portion GA3 is formed to be spaced apart from the second gap GB2 and the second end portion GC2, whereby the coil electrode 6T is formed at both end portions of the third coil 6C.

Next, as shown in fig. 4 (h), the resist layer R remaining on the surfaces of the first to third coils 6A to 6C is removed using a stripping solution or the like (resist removal step).

Then, the linear sensor 1 is orthogonally bent at the first gap portion GQ1 and the second gap portion GQ2, thereby forming the MI sensor 1A in which the X-axis coil 6X, Y and the Z-axis coil 6Z are orthogonal to each other (bending step).

As described above, in the method of manufacturing the MI sensor 1A according to the present embodiment, the MI sensor 1A integrally including the X-axis coil 6X, Y and the Z-axis coil 6Z can be manufactured. Thus, when the MI sensor 1A is mounted, it is not necessary to combine a plurality of MI elements, and therefore, the mounting work can be simplified.

In the MI sensor 1A according to the present embodiment, when the amorphous wire 2 is energized, the first terminal GT1 and the second terminal GT2 are connected to each other to allow a pulse current to flow. That is, since two lines for conducting current to the amorphous line 2 can be provided, the mounting can be made easier than the conventional configuration in which three MI elements are wired separately.

In the method of manufacturing the MI sensor 1A according to the present embodiment, the insulating layer 3 is formed to have a uniform thickness in the circumferential direction by forming the outer peripheral shape of the insulating layer 3 in the cross section into a circular shape in the insulating step. This makes it possible to keep the distance between the amorphous wire 2 and the coil 6 formed on the outer peripheral surface of the insulator layer 3 constant without leaving a space. Specifically, the insulator layer 3, which is a material having a known magnetic permeability or dielectric constant, may be used to concentrically fill the gap between the amorphous wire 2 and the coil 6. Therefore, the electric loss in the coil 6 can be reduced, and thus the sensitivity of the MI sensor 1A can be improved.

More specifically, in the MI sensor 1A of the present embodiment, the insulator layer 3 having a circular shape is formed on the surface of the amorphous wire 2 having a circular shape in a cross section, and thus the thickness of the insulator layer 3 is uniformly formed in the circumferential direction. Therefore, the distance between the amorphous wire 2 and the coil 6 can be set constant without depending on the position in the circumferential direction. As a result, variations in the detection accuracy of the MI sensor 1A can be reduced, and therefore, individual differences of the MI sensor 1A can be suppressed. In addition, in the method of manufacturing the MI sensor 1A of the present embodiment, even by making it possible to manufacture a plurality of MI sensors 1A at a time in the same process, individual differences of the MI sensors 1A can be suppressed.

Further, in the MI sensor 1A of the present embodiment, the pulses applied to the core wires of the coil 6 arranged in the X, Y, Z directions can be unified without being connected to the outside. That is, the same stimulation pulse can be applied to the sensors (coils 6) in each direction without strict management. Thereby, generation of individual difference in the X, Y, Z direction of the MI sensor 1A can be suppressed. Since the X-axis coil 6X, Y and the Z-axis coil 6Z are orthogonal to each other, mutual inductance is not generated.

As described above, according to the method of manufacturing the MI sensor 1A of the present embodiment, the MI sensor 1A can be manufactured in which the mounting work can be simplified, the electric loss can be reduced by making the distance between the amorphous wire 2 and the coil 6 without leaving a space, and the occurrence of individual difference and individual difference in the X, Y, Z direction can be suppressed.

In the MI sensor 1A of the present embodiment, the coil electrodes 6T in the form of a ring are formed at both ends of the X-axis coil 6X, Y and the Z-axis coil 6Z so as to surround the insulator layer 3. Accordingly, the wires 7X to 7Z can be connected to the coil electrode 6T regardless of the posture of each of the coils 6X to 6Z, and therefore, the mounting work can be performed more easily.

< MI sensor 1B (second embodiment) >

Next, the structure of the MI sensor 1B according to the second embodiment of the present invention will be described with reference to fig. 5. In the present embodiment, the configuration common to the MI sensor 1A of the first embodiment is not described in detail, and a different configuration will be mainly described.

As shown in fig. 5, the MI sensor 1B of the present embodiment is manufactured by fixing the X-axis coil 6X as the first coil, the Y-axis coil 6Y as the second coil, and the Z-axis coil 6Z as the third coil arranged in the bending step through the resin mold P as the fixing portion (fixing step). More specifically, the resin mold P is formed into a rectangular parallelepiped, and each surface is formed into a shape orthogonal to the X axis, the Y axis, and the Z axis. In other words, the X-axis coil 6X, Y, the axial coil 6Y, and the Z-axis coil 6Z are housed in the internal region (region filled with the resin mold P) of the rectangular parallelepiped formed by the resin mold P, and are fixed and arranged in the direction orthogonal to the respective surfaces forming the surface of the resin mold P.

According to the present embodiment, since the relative positions of the X-axis coil 6X, Y and the Z-

axis coil

6Y and 6Z can be fixed, the positions of the X-axis coil 6X, Y and the Z-axis coil 6Z can be determined only by determining the position of the resin mold P. That is, the MI sensor 1B can simplify the mounting work more than the MI sensor 1A of the above embodiment.

As a method for fixing the X-axis coil 6X, Y and the Z-axis coil 6Z by the fixing portions in the MI sensor 1B, other methods such as a fixing method by a jig or a method for fixing the coils by filling a sealant around the coils may be employed instead of the method of molding P with a resin employed in the present embodiment.

That is, an MI sensor according to an example of the present invention includes: a linear magnetic conductor; an insulator layer formed on an outer peripheral surface of the magnetic conductor; and a first coil, a second coil, and a third coil that are formed in a spiral shape on an outer peripheral surface of the insulator layer, wherein the first coil, the second coil, and the third coil are formed of a conductive layer, and the first coil, the second coil, and the third coil are arranged in mutually orthogonal directions.

According to the above configuration, the mounting work can be simplified, the electric loss can be reduced by making the distance between the magnetic conductor and the coil constant without leaving a space, and the occurrence of individual differences of the respective MI sensors and individual differences of the MI sensors in the direction X, Y, Z can be suppressed.

In addition, the MI sensor is preferably configured such that the first coil, the second coil, and the third coil are fixed by a fixing portion.

According to the structure, the installation operation can be further simplified.

In addition, the MI sensor is preferably configured such that both end portions of the first coil, the second coil, and the third coil are formed as annular coil electrodes that surround the insulator layer once.

According to the above configuration, the MI sensors can be manufactured in which the mounting work can be simplified, the electric loss can be reduced by making the distance between the magnetic conductor and the coil constant without leaving a space, and the occurrence of individual differences of the MI sensors and the individual differences of the MI sensors in the X, Y, Z direction can be suppressed.

In addition, the method for manufacturing the MI sensor preferably includes a fixing step of fixing the first coil, the second coil, and the third coil arranged in the bending step by a fixing portion.

According to the above configuration, an MI sensor capable of further simplifying the mounting work can be manufactured.

In the method for manufacturing the MI sensor, it is preferable that the exposure step includes forming a first end portion that surrounds the resist layer on an outer peripheral surface of the resist layer on an outer end side of the first trench portion, forming a second end portion that surrounds the resist layer on an outer peripheral surface of the resist layer on an outer end side of the third trench portion, and forming the first end portion, the first trench portion, the first gap, the second trench portion, the second gap, the third trench portion, and the second end portion so as to be spaced apart from each other, and the etching step includes forming the conductive layers remaining on both end portions of the first coil, the second coil, and the third coil into annular coil electrodes that surround the insulator layer.

According to the method of manufacturing an MI sensor and the MI sensor of the embodiment of the present invention, the mounting work can be simplified, the distance is fixed without leaving a space between the magnetic conductor and the coil, the electric loss can be reduced, and the occurrence of individual differences of the MI sensors and the individual differences of the MI sensors in the direction X, Y, Z can be suppressed.

The present application is based on the japanese patent application laid-open at 27.6.2018, japanese patent application No. 2018-121668, and the contents thereof are included in the present application. The specific embodiments and examples mentioned in the description of the embodiments are merely illustrative of the technical contents of the present invention, and the present invention should not be construed narrowly limited to such specific embodiments.

Description of the symbols

1: linear sensor

1A: magneto-impedance sensor (MI sensor)

1B: MI sensor

2: amorphous wire (magnetic conductor)

3: insulator layer

4: electroless plating layer

5: electrolytic coating

6: coil

6A: first coil

6B: second coil

6C: third coil

6T: coil electrode

6X: x-axis coil

6Y: y-axis coil

6Z: z-axis coil

7X: wiring harness

7Y: wiring harness

7Z: wiring harness

R: resist layer

P: resin molding (fixing part)

GA 1: first channel part

GA 2: second channel part

GA 3: third channel part

GB 1: first gap

GB 2: second gap

GC 1: first end part

GC 2: second end portion

GP 1: a first groove part

GP 2: the second groove part

GP 3: third groove part

GQ 1: first gap part

GQ 2: second gap portion

GT 1: first terminal

GT 2: second terminal

Claims

1. A magnetic impedance sensor comprising:

a linear magnetic conductor;

an insulator layer formed on an outer peripheral surface of the magnetic conductor; and

a first coil, a second coil, and a third coil formed spirally on an outer peripheral surface of the insulator layer, and in the magneto-impedance sensor,

the first coil, the second coil, and the third coil are formed of an electrically conductive layer,

the first coil, the second coil, and the third coil are arranged in mutually orthogonal directions.

2. A magneto-impedance sensor as recited in claim 1, wherein the first coil, the second coil, and the third coil are fixed by a fixing portion.

3. A magneto-impedance sensor according to claim 1 or 2, wherein both end portions of the first coil, the second coil, and the third coil are formed as ring-shaped coil electrodes that surround the insulator layer once.

4. A method of manufacturing a magneto-impedance sensor, comprising:

an insulating step of forming an insulator layer on an outer peripheral surface of the linear magnetic conductor;

a conductive layer forming step of forming a conductive layer on an outer peripheral surface of the insulator layer;

a resist step of forming a resist layer on an outer peripheral surface of the conductive layer;

an exposure step of forming a first channel portion, a second channel portion, and a third channel portion in a spiral shape on an outer peripheral surface of the resist layer by exposing the resist layer with laser light, respectively, forming a first gap around the resist layer between the first channel portion and the second channel portion on the outer peripheral surface of the resist layer, and forming a second gap around the resist layer between the second channel portion and the third channel portion on the outer peripheral surface of the resist layer;

an etching step of etching the resist layer as a cover material to remove the conductive layer in the first channel portion, the second channel portion, the third channel portion, the first gap, and the second gap, thereby forming a first coil from the conductive layer remaining around the first channel portion, a second coil from the conductive layer remaining around the second channel portion, and a third coil from the conductive layer remaining around the third channel portion; and

and a bending step of bending the magnetic conductor and the insulator layer between the first coil and the second coil and between the second coil and the third coil, thereby arranging the first coil, the second coil, and the third coil in directions orthogonal to each other.

5. A method for manufacturing a magneto-impedance sensor according to claim 4, comprising a fixing step of fixing the first coil, the second coil, and the third coil arranged in the bending step by a fixing portion.

6. The method of manufacturing a magneto-impedance sensor according to claim 4 or 5, wherein in the exposing step, a first end portion that surrounds the resist layer is formed on an outer end side of the outer peripheral surface of the resist layer that is further from the first channel portion, a second end portion that surrounds the resist layer is formed on an outer end side of the outer peripheral surface of the resist layer that is further from the third channel portion, and the first end portion, the first channel portion, the first gap, the second channel portion, the second gap, the third channel portion, and the second end portion are formed so as to be spaced apart from each other,

in the etching step, the conductive layers remaining at the respective end portions of the first coil, the second coil, and the third coil are formed as ring-shaped coil electrodes that surround the insulator layer once.